預防流感,哪種口罩最有效
【英文原文】
Small-particle filters offered nurses no better protection against the flu than standard surgical masks, according a study in JAMA. While the filters, called N95 respirators, can catch a much wider range of airborne pathogens, they are more expensive and in much shorter supply than the masks — of great concern during a flu pandemic. While some public-health organizations have recommended respirators over masks, and other organizations masks over respirators, this was the first published randomized trial comparing their effectiveness in preventing influenza. The 446 Canadian nurses in the study were assigned to wear either masks or N95 respirators while treating patients with respiratory illness and signs of fever over a roughly three-month period. By the end, 23.6% of nurses who wore surgical masks had gotten the flu, compared with 22.9% of the nurses who wore N95 respirators — a statistically insignificant difference. Similarly, there was no significant difference in the rates of H1N1 influenza, or swine flu, between the two groups.
Caveat: The study did not evaluate other factors, such as hand hygiene, that have been shown to affect influenza transmission. Additionally, the researchers had only limited data regarding how often the nurses wore the protective devices to which they were assigned.
【中文譯文】
《美國醫學會雜誌》(JAMA)的一項研究表明，與普通的外科口罩相比，微粒過濾口罩並不能更有效地幫助護士預防流感。儘管名爲N95呼吸防護口罩的這種過濾口罩能夠捕捉到更多的依靠空氣傳播的病原體，但它們的售價更高，而且與外科口罩相比供應量也大大不足──這在流感大爆發的情況下不免令人擔 。有些公共衛生組織建議使用呼吸防護口罩，而有些組織則推薦外科口罩。《美國醫學會雜誌》的這一研究是比較兩種口罩在預防流感方面有效性的第一份隨機性的評估報告。在大約三個月的時間裏，參與此項研究的446名加拿大護士在護理患有呼吸系統疾病和發燒症狀的病人時被指派佩戴外科口罩或者是N95呼吸防護口罩。研究結果顯示，佩戴外科口罩的護士中有23.6%患上了流感，而佩戴N95口罩的護士中有22.9%患上了流感──這一差別並不具有統計學上的意義。與此相似，在H1N1，也就是豬流感的傳播病例中，兩組護士也沒有顯著性差異。
提示：此項研究並未評估其他因素，比如說已經被證明能夠影響流感傳播的手部衛生。此外，在護士們口罩佩戴時間長短的問題上，研究人員也只獲得了有限的數據。
